DEVELOPING: At least 12 people are dead, including four Europeans, after gunmen stormed a popular Ivory Coast beach resort Sunday frequented by Westeers, according to Reuters, which cited police sources.

"We don't know yet if there are others," an officer told security forces during a briefing also attended by a Reuters reporter. "We are doing clean-up operations right now."

A large military deployment was on the scene, The Wall Street Joual reported, citing state media.

The gunfire reportedly occurred at a hotel in Grand-Bassam and several people were wounded, diplomatic sources told Reuters. Four gunmen were involved in the attack, a witness told Reuters.

The attackers, who were "heavily armed and wearing balaclavas, fired at guests at the L'Etoile du Sud, a large hotel which was full of expats in the current heatwave," a witness told AFP.

"I saw seven dead that I filmed. There were four attackers. I was swimming when it started and I ran away," said Dramane Kima, who showed video of the caage to Reuters. He also took pictures of grenades and ammunition clips he believed were left behind by the gunmen.

Josiane Sekongo, who lives across from one of the town's many beachfront hotels, said she ran outside when she heard the gunfire and saw people ruing away from the beach. Sekongo, 25, said residents were hiding in their homes as security forces responded.

It was unclear how many assailants were involved. Casualty information was not immediately available.

The gunmen were not identified and it was unclear if they were with a militant group, according to Reuters.

Luc Gnago, a witness to the shooting, told Sky News the shooting was over and the beach was "empty" apart from soldiers and "a few people looking after the bodies."

An AFP reporter saw a dozen people being evacuated from the area by the military.

A dozen ambulances, military vehicles with heavy machine guns and armed traditional hunters were at the scene, according to Sky News.

Attacks by Islamists on hotels frequented by foreigners in two other West African countries, Mali in November and Burkina Faso in January, killed dozens of people and indicated that extremist attacks are spreading from North Africa.

Grand-Bassam, which was named a UNESCO World Heritage Site in 2012, is known for its colonial buildings. The U.S. embassy is located about 45 minutes away from Grand-Bassam.

An American embassy delegation was in Grand-Bassam on Sunday but the U.S. Embassy in Abidjan said it is monitoring the situation in Grand-Bassam and there is no evidence that U.S. citizens were targeted nor confirmed reports of any U.S citizens harmed.

The Associated Press contributed to this report.